Hurricane Irene (2011)
Hurricane Irene (2011) is an Atlantic Hurricane of the season 2011. On August 15, 2011, a tropical wave exited the African coast dropping into the Atlantic, characterized by distinct low-level cyclonic rotation and deep tropical moisture.[1] It remained well-defined while moving steadily westward for several days through the Cape Verde Islands, although at the time any notable convection occurred well to the southwest of its axis.[2] As the wave distanced itself from the islands, development of thunderstorms and showers in its proximity continued to remain scarce, and it became rather broad in appearance.[3] On August 19, the convective structure began to show signs of organization as the associated atmospheric pressure lowered, and with a progressively favorable environment situated ahead of the wave its chances of undergoing tropical cyclogenesis markedly increased.[4][5] The strong thunderstorm activity continued to become more pronounced around the main low-pressure feature; by August 20, the National Hurricane Center (NHC) noted that tropical cyclone formation was imminent as the wave neared the Lesser Antilles.[6] A reconnaissance aircraft confirmed the presence of a small surface circulation center just southwest of a burst of vigorous convection and unusually high sustained winds, which indicated sufficient organization for the low to be upgraded into Tropical Storm Irene at 2300 UTC that day. Upon being classified, Irene was positioned about 190 mi (305 km) east of Dominica along weakening high pressure over the west-central Atlantic, inducing a roughly west-northwestward path for most of its journey through the eastern Caribbean.[7] Its mid-level circulation continued to become better established as hints of pronounced banding features curved north of the surface center.[8] On August 21, the surface center reformed closer to the deepest convection; furthermore, an anticyclone aloft provided supportive outflow over the cyclone. With the improved structure, as well as light wind shear and high sea surface temperatures, Irene was forecast to strengthen to near hurricane force prior to landfall in Hispaniola.[9][10] Over the subsequent day, Irene traced more northward than initially expected—while passing near the island of Saint Croix[11]—toward Puerto Rico, where it underwent a considerable increase in strength and organization.[12] Hours later, Irene moved ashore to the southeast near Punta Santiago, with estimated sustained winds of 70 mph (110 km/h).[13] Despite interaction with land, a ragged eye-like feature became evident on radar imagery; in addition, Doppler data indicated wind speeds in excess of hurricane force. Irene was accordingly upgraded to a Category 1 hurricane—the first of the annual season—just after its initial landfall.[14] With the storm then situated just north of the mountainous coast of Hispaniola, the cyclone deepened only briefly after reemerging over water, and any additional organization during the rest of the day was gradual.[15][16] Although Irene briefly weakened on August 23,[17] it began to develop a distinct eye encircled by an area of deepening convection the next morning. Moving erratically through the southeast Bahamas over very warm waters,[18] Irene quickly expanded as its outflow aloft became very well established; the cyclone intensified into a Category 3 major hurricane within hours.is currently undergoing what seems like an [http://en.wikipedia.org/wiki/Eyewall_replacement_cycle eyewall replacement cycle, which has weakened the hurricane temporarily